Clara Oswin Oswald

Clara Oswin Oswald.  One of the complexities of the show, naturally, as she was created to be.  Some will look to the episodes mentioning things familiar for her, however that is not where to look.  Look for the more obscure.  A theory that is strong in my mind is simple, really, but not one people would think of.  How many of you out there remember the flesh doppelgangers?   Imagine if there were a more advanced form wherein the consciousness could be in multiple bodies at the same time.  The bodies a bit stronger than human bodies, yet still very capable of death and disaster.  The bodies would be virtually human, yet identical with each other, scattered throughout time.  Death is more difficult, but it still happens, but there are new bodies there to fill the place.  Basic knowledge, but no capability to remember what the previous body learned.  Because of that, she has to tell the Doctor to remember, because she knows that she can't.